John. All aviation, marine and land transport (train) accidents / incidents etc are investigated and a Report published.
In the NZ case the Police assist with the task. I am not sure how the report may affect a coroners Report. I understand charges can not be laid based on the accident / incident report by the Transport Accident Investigation Commission. (TAIC).
I still can't see why the ATSB at least attend and report on any Fatal accidents involving RAAus, HGFA and ASRA etc.